In the construction industry, levels are used to ensure that structural members are installed in their exact intended orientations. Levels include plural vials, almost always including a principal center vial which is parallel to a reference surface and used to indicate a horizontal orientation. Such horizontal vial is normally secured to the level frame in a position that permits viewing of the vial from both sides and also from above to ascertain the orientation of substantially horizontal surfaces. The most desirable positioning of such vial is within a topnotch in the body of a level which topnotch is defined by two sidewalls and the topwall of a hollow level body frame. However, such positioning also presents a challenge for securing the vial to the frame. Because of the open nature of the topnotch, the vial is prone to becoming disassembled from the frame upon various impacts caused by the occasional dropping of the level or other disruptive occurrences at a construction site.
There have been various prior arrangements for mounting horizontal vials within the topnotch. Such arrangements, however, have problems and disadvantages rendering them problematic in many situations. Certain devices of the prior art are disadvantageous in requiring glueing of the mounting structure to portion of the level body. Some such prior arrangements are designed to secure the vial by extending forces directed away from each other to engage inner surfaces of opposite walls of the level frame, but such arrangements have disadvantages related to adaptability for varying level sizes and in some cases related to ease of assembly.
One example of such arrangements is described in United States Patent Application Publication No. 2005/0160610 to Scheyer. Scheyer uses a two-part mounting system with one part which holds the vial, forced against an inner surface of a bottom wall, and another part drawn against an inner surface of the opposite (top) wall. The problem of such construction is that the vial-holding part has to be accurately dimensioned for a particular level size such that this vial-holding part spans the distance between top and bottom walls to hold the vial at the correct position along the topwall. Another example of such arrangements is described in JP 2007-24790 (Feb. 1, 2007), but such arrangement pose difficulties in assembly because of the to need to gain access to internal fasteners from the end of the level body.
There is a need for an improved level which overcomes the aforementioned problems. It would be desirable to have a versatile vial-mounting structure that is suitable for levels of various sizes without any special dimensioning of the mounting structure for specific sizes. It would be desirable to develop a vial-mounting structure which is accurately and reliably secured the level body and does so without difficult assembly steps and without the need for glueing of the structure to the body. Accurate mounting of the vial-mounting structure to the level body facilitates accurate vial orientation.